CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net Income (Loss)	$ 195,433	$ 298,209	$ 213,521
Postretirement benefit plans:
Net actuarial gain (loss), net of tax of: (2023 - $294; 2022 - $1,144; 2021 - $451)	(847)	3,298	1,300
Amortization of unrecognized net periodic benefit cost (credit), net of tax of: (2023 - $342; 2022 - $195, 2021 - $139)
Net actuarial gain	(988)	(562)	(400)
Interest rate swap and foreign currency translation:
Change in unrealized gain (loss) on interest rate swap, net of tax of: (2023 - $475; 2022 - $812, 2021 - $534)	(1,341)	2,295	1,507
Change in foreign currency translation, net of tax of: (2023 - $141; 2022 - $576, 2021 - $36)	397	(1,627)	102
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(2,779)	3,404	2,509
TOTAL COMPREHENSIVE INCOME	$ 192,654	$ 301,613	$ 216,030